Tunnel-furnace.



`. H. COWLES.

TUNNEL FURNACE.

APPLICATION FILED 11924. 1911.

Patented Oct. 8, 1912.

' i@ mm m ENTOR "di I LQ ATTORNEY lU NITED STATE@ PATENT @llltlltl ALFRED H.

COWLES, 0F SEWAREN, NEW JERSEY, ASSIGNOR T0 THE ELECTRIC SMELT'- ING AND ALUMINUM COMPANY, OF SEXVAREN, NEW JERSEY.

ToNNEL-FURNACE.

Specification of Letters Patent.4

Patented oer. s, 1912.

Original application filed April 14, 1911, Serial No. 62?.,002. Divided and this application filed August 24; 1911. Serial No. 645,868.

.To all whom 'it may concern:

.Be it known that I, Amano H. Cowmis, a citizen oitl the lnit'ed States, and a resident of Scwaren, in the county ol Vliddlesex and State of New Jersey, have invented certain new and uset'ul Improvements `in '.llunuel- Furnaces, of which the il'ollowng is a speci* fication,

My invention relates to tunnel -furnaces.

lt relates particularly to a new and improved :furnace and to means vtor protecting` portions of the furnace and the conveving device from the action of injurious gases7 or liquids, developed during the, oiiieration ol the furnace.

The invention is particularly adapted for use in connection with the manufacture ot' hydrochloric acid from clay or aluminous materials.

The object of the invention is to allow' the use ot' tunnel furnaces under ctnulitions where the ga'iseous products Aformed in the heated zone above the cars are o'll an aciil nature and such that upon cooling they attack the metal portionsol the cars and thcl concrete parts oi' the masonry in the tunnel structure.

To carry out my invention I introduce into the portion ot' the furnace under the cars air, or an inert gas, that is, a that does not attack the corrodible parts ot' the cars orfol the furnace, under such pressurev as t0 Counterbalance any pressure of the acid fumes tending to force such acid lmnes downward and around the cars.

In the drawings acconu'ianying and vforming part oi thisapplication, are shown, by Way of example, means for arrying out my invention, and therein:

Figure 1 is an elevation ot Va lfnrnaee showing one of my attachments; Fig. 2 is a longitudinal section through the lfeet'ling end of the furnace and the vestibule; Fig. 3 is a cross-section on the line 33 ot'yiFig. i. Fig. 4 is a. longitudinal section near the eentral and hot-test zone; Fig. 5 is a section near the outlet of the furnace, and Fig. 6 is a detail showin-g an air baille.

Referring to the drawings; 1, is the fur4 nace provided with the vestibule 2; 3 is a blower forcin air, or an inert gas, through conduit 4 ant inlets 5 into the lower part 10 of the furnace 1; 6 are the cars loaded with briquets 7, and 8 is the transfer car by which the loaded car is brought in't'o the vestibule; 9 is the sand seals for Sealing the space above the ears 'from the space belo'v.' the same; l1 is the device shown as ele'ct'rically o];\erated. t'or in'iparting to the cars G gradual and 'l'orward movement tl'irough the l'urnace; 12 shows means for operating. the door 12'3 between the vestibule and t'he 'fui'- nacc, and l" are means for operating the two cud doors ot the vestibule; 13 are sand seals tor sealingtwo sides of the vestibule pit, the other two sides heilig provided with sand seals; 15 is a pressure regulating valve inserted in the air inlet pipes 5.

ll and 17 are pressure regulating valves provided aty the entrance end oi'l the furnace and vestibule respectively, and 171 is a pipe connecting these two Valves; 18 are the oil burner holes and 19 an inlet. for steam and air.

Q0 is the suction fan for drawing the acid Vl'uines l'rorn through the pipe. 21 and conveying them to the acid towers, or other receptacles, through the pipe 22; 33 arc air battles for hindering the exit ot the air atl the discharge end ot' the furnace.

'l`he operation 'is as follows: Assume the portion 0 of the furnace to be lilled with cars loaded with briquets ol. such a composition that the product to he drawn oil' by the suction fau 20 is to be hydrochloric acid vl'umcs, mixed with water vapor and lproducts o lf eombust ion, and assume a car to be. ready to cuter the, Alurnace7 as shown in Fig. lhe gas jets 1S having been lighted, steam and airarcblown in at 19 over the tops ol" thc :ulvainfiugV ears. The mechanism i2 operates the door 13', and the car enters, urged forward by the electrical pusher 11. As soon as the ear t3 has entered the furnace, the door lill ot' the vestibule is closed, the side vestibule door opened', and the transfer car S enters with a new loaded car ready to be advanced into the furnace.

Shortly after starting the operation acid `fumes begin to lill the portion 9 above the tops of the cars, and these are sucked out by means o't' the t'an 20. These acid fumes (here assumed to be hydrochloric aei'd fumes) in the state 'or vapor do not attack the iron, but it cooled below the temperature the furnace above the cars` at which they condense with water (say at about 220 degrees F), they readily attack and destroy thel iron work f the cars andv The essential thing is to prevent any leakagev of the acid fumes downward, and to cause whatever leakage there is Ito be directed upward from below the points where the temperature is lower than the condensation point of the fumes, and l create a pressure of air or inert gas, upward. from beneath the cars equal, or exceeding that dmvnward. The pressure may be produced in one way by a blower 3 delivering air through a pipe t, arrangedon one or both sides of the furnace, through the holes '5 and into the furnace below the cars, the position and number of the holes depending upon the heat and pressure in different parts of the furnace. The air introduced may, under cer-- tain circumstances be hot and thus assist in preventing' the'lower portion of the furnace from becoming cold, so that the deposition of the acid fumes takes place. Moreover, each of the air inlet pipes may be provided with regulating valves 15, so that the desired pressure may be maintained. There must be means of control, because otl'ierwise too much air i'night be forced upward through the crevices between and around the cars from below, and the heating gases be unduly cooled or their proper composition interfered with. The ideal to be sought is a balance, or slight upward pressure of the air. llt is evident in the specific illustration shown, that the downward pressure will be greatest at a point where the rburning gases are hottest and where the gas jets are most closely grouped, and it is for this that l have shown the air inlets 5 most closely grouped in Fig. d, which indicates the mid dle of the furnace, or the part where the gas jets are most numerous and hottest. The suction fan for duwing off the acid fumes is shown as located at the entering end, and as the leakage at that end would be naturallyT upward, l have shownno air inlets at this point. At the outlet end the blowing in of steam through the pipe 19 creates, at that particular spot, a tendency to an upward pressure, on account of the partial vacuum created, but further on in the fur-- nace this entering steam might create a downward pressure. On account of this partial vacuum at the outlet end l have shown few air inlets at thatpart of the furnace.' Of course, as there' are regulating readers valves attached to each of the air inlets, they may be scattered as thickly from end to end as desired along` the furnace, the pressure thus being under absolute control. Great pressure is not needed, especially at the ends. As the furnace is opcnat the outlet end, and cars are passed out continually, there would be a tendency for considerable air to escape from under the cars at that end. I have therefore devised and herein shown one simple manner of preventing too great escape of air from under the cars. I place crosswire in the pit of the car track a flexible metal sheet,

which ills the opening close up to the lootl tom of the car. The elastic limit of the metal is so chosen that when the advancing car axle meets it and bends it over, as shown in dotted lines in Fig. it resumes its original shape as soon as the car axle has passed. Each axle in passing operates the sheet metal baille, and by placing several of them grouped closely, as shown in Fig. 5, no great rush of air to or out of that end takes place.

Another way in which the escape of air could be prevented to a very large extent, would he to blow air in under the cars against the air rushing into the outlet end and by the valves shown producing the balance of the two currents. There could also be attached to the sides of the cars or of the furnace means for filling` up the space between the sides of the car and the furnace and the space around the wheels, if that were thought desirable to produce a more perfect control of the air at the out-let end of the furnace.

'1`o control the pressure in the vestibule and in the furnace, l have arranged the pressure regulating valves 16 and 17 and the pipe 171 connecting the lower part of th furnace and the lower part of the vesti bu e.

brought in by the transfer car 8, the valve 17 is closed, and thereby the pit is sealed against the escape of air. The vestibule being openech'thel pressure therein becomes, (if course, that of the atmosphere. i

lfVhen the vestibule is ready for the door 131 to be lifted for a car to be admittedto the fui1iace,"tlie air pressure is raised to that of the furnace by means of 3, or some other convenient source. The' valve 17 is then closed and the door between the furnace and vestibule opened.

I do not herein claim the method which my invention is adapted to carry out, that formingl the subject matter of my co-pending application.y Ser, No. 621,002, filed April inn, 191i, but

1. An apparatus for .making hydrochloric acid comprising a tunnel furnace provided with means for drawing ott the injurious lWhen the vestibule door 13l is to be' .lowered so that a new loaded car may be ases produced in the upper part of the urnace above the cars, means for maintaining the lases in the lower portionof the furnace a ve atmospherlc pressure, in coin- \-.,bination with means for supplying inert vided With a car track, cars runningon said track and dividing the furnace into an upper and lower portion, said -furnace being vprovided above the car tops with a gas heatlng source and means at the exit end for introducing steam and air, and having, moreover, connected with the top of the furnace near the car entrance a Suction device for drawing olf the acid fumes, formed in' the top of the furnace, in combination nvith .means for supplying inert gas, means for maintalning t-he inert gas above the atmospheric pressure so as to counterbalance the .pressure of the acid fumes downward and eepthem from penetrating belowthe car tops and attacking the corrodible portions of the cars and of the furnace.

3. An apparatus for manufacturing hydrochloric acid, comprising a tunnel furnace open at the exit end, a car track, a car it, loaded cars located on said track and dividing the it from the upper portion, said` furnace eing provided in the upper portion with a supply of steam and air, having, moreover, a suction device connected with the top of the furnace near the car entrance, and means for supplying inert gas to the pit, all in combination with gas baffles in the pit near the exit end and automatically operated by the moving cars.

4. An apparatus for making hydrochloric acid from aluminous. material and an alkali chlorid, comprising a tunnel furnace provided with a car track, a car pit, a suction device connected with the top of the furnace near the car entrance, in combination with a valved pipe located also near the car entrance and in the car pit and adapted 'to' regulate the pressure of the gases in the car pit.

5. An apparatus for'making hydrochloric acid, comprising a tunnel furnace having a vestibule provided with a car pit, said it Ibeing provided with sand seals, 1n coin ination with a pipe provided with an adjustable valve adapted to control the gas pressure in the vestibule car pit.

G. A tunnel furnace comprising an upper portion and a car pit-and havin a suctlon device connected with the top o the upper portion 4near the entrance, m combination with a regulating valved pipe located also near the entrance and in the car pit.

7. A'tunnel furnace comprising a vestibule having a car pit, said pit being provided wit-h sand seals, in combination with a pipe provided lwith an adjustable valve adapted to control'the gas pressure in said pit. y Signed at Sewaren in the county of Middlesex and State of New Jersey this 14th day of August A. D. 1911. i

ALFRED H. COWLES. 

